BNL FNAL LBNL SLAC U S LARP Magnet

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BNL -FNAL - LBNL - SLAC U. S. LARP Magnet Programme P. Wanderer IR’

BNL -FNAL - LBNL - SLAC U. S. LARP Magnet Programme P. Wanderer IR’ 07 - Frascati 7 November 2007

Progress: 2003 - 2007 Goal: Demonstrate “long strong” Nb 3 Sn quad by the

Progress: 2003 - 2007 Goal: Demonstrate “long strong” Nb 3 Sn quad by the end of 2009 Focus: develop “building blocks” for Nb 3 Sn magnets • Materials: high current, stable Nb 3 Sn conductor • Model Magnets: 200 T/m, two support structure designs • Supporting R&D: early development of long (3. 6 m) Nb 3 Sn coils with racetrack coils and one of the support structures; insulation, quench protection, cooling … • IR Design Studies: magnet designs for possible IR optics (e. g. , dipole first), magnet designs for larger aperture/ higher gradient quadrupoles 2

Plans: 2007 - 2009 Goal: Demonstrate “long strong” quad by the end of 2009

Plans: 2007 - 2009 Goal: Demonstrate “long strong” quad by the end of 2009 LQ (long quad): working to build, test 1 -3 3. 6 m, 90 mm quads by the end of 2009; support structure review at the end of November. Highest LARP magnet priority Materials: increase Nb 3 Sn strand diameter, improve understanding of strain sensitivity. HQ (high gradient/aperture) : design, build 130 mm aperture quads use in Phase I (2012)? ? JIRS (Joint IR Studies): joint magnet, accelerator studies, first priority: Phase I upgrade 3

This talk: Materials Model Magnets Next talks: HQ – G. Sabbi LQ – G.

This talk: Materials Model Magnets Next talks: HQ – G. Sabbi LQ – G. Ambrosio JIRS – A. Zlobin 4

MATERIALS – STATUS AND PLANS Nb 3 Sn conductor developed to yield current-carrying capacity

MATERIALS – STATUS AND PLANS Nb 3 Sn conductor developed to yield current-carrying capacity and magnet stability suitable for 200 T/m, 90 mm aperture quads. This material, called RRP, is now a “standard product. ” (US DOE Conductor Development Program, lab “base” programs helped. ) Next steps: Develop larger-diameter strand (needed for larger magnets) this requires more, smaller filaments Test cables (as opposed to testing “extracted” strands) 5

Increase Subelement Spacing RRP Strand Development with OST (Fermilab) Increase Subelement Number 54/61 restack

Increase Subelement Spacing RRP Strand Development with OST (Fermilab) Increase Subelement Number 54/61 restack Jcmax~3000 A/mm 2 60/61 restack with spaced SE’s Jcmax 3000 A/mm 2 RRP 0 108/127 restack Jcmax~2400 A/mm 2 RRP 1 114/127 restack with spaced SE’s Jcmax~3000 A/mm 2 6

TQ Data: BNL-FNAL-LBNL 1. 9 K calc Ic calc +/- 0. 1% strain 7

TQ Data: BNL-FNAL-LBNL 1. 9 K calc Ic calc +/- 0. 1% strain 7

Strand Production 8

Strand Production 8

RRP-8648, 0. 7 mm RRR ~ 310 (2. 09 K) 9

RRP-8648, 0. 7 mm RRR ~ 310 (2. 09 K) 9

Model Quadrupole Program Technology Quadrupoles (TQ) 1 m long, 90 mm aperture Coils made

Model Quadrupole Program Technology Quadrupoles (TQ) 1 m long, 90 mm aperture Coils made jointly by Fermilab and LBNL Support structure options: TQC: “collar” support TQS: “shell” support 10

TQC Mechanical Structure Azimuthal preload applied via collars and via shell. Axial preload keeps

TQC Mechanical Structure Azimuthal preload applied via collars and via shell. Axial preload keeps coil ends in (light) contact with structure 11

TQS Mechanical Structure Azimuthal preload applied via inflatable/removable bladders and keys. Axial preload high

TQS Mechanical Structure Azimuthal preload applied via inflatable/removable bladders and keys. Axial preload high (via rods) 12 12

Quench test: same coils in both structures: Initial test: TQS 02 Subsequent test: TQC

Quench test: same coils in both structures: Initial test: TQS 02 Subsequent test: TQC 02 E (E = exchange) note: RRP conductor Results: Both quads reached ~ 90% of the expected maximum performance of the conductor at 4. 5 K (no correction for reduction in current-carrying capacity for strain) Their gradients differ because the ratio G/I is not the same. Neither magnet improved at 1. 9 K. This is not yet understood. 13

TQS 02 a Training TQS 02 a 180 to 220 T/m, 20 quenches Plateau

TQS 02 a Training TQS 02 a 180 to 220 T/m, 20 quenches Plateau coil 21 layer 2 No gain at 1. 9 K Quench 1: inner layer pole turn, ramp and multi-turn Quench 2 -3: outer layer multiturn followed by return end. Quench 4: inner layer pole turn and multi-turn segment inside wedge. Quench 5 -6: outer layer multiturn followed by pole turn. From # 17 all quenches (both 4. 5 K and 1. 9 K) start in the outer layer of coil 21. Quench 8 to 16, inner layer of coil 20, in the turns inside the wedge. Video conference October 3, 2007 14 14

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Quench data - two additional model quads (TQ) TQS 01 a, b, c Three

Quench data - two additional model quads (TQ) TQS 01 a, b, c Three tests varying coils (i. e. , replace the worst performing coil) and end preload. MJR (“old style” conductor) Result: reached ~ 90% of conductor limit at 4. 5 K, did not advance much beyond this at 1. 9 K. TQC 01 a, b Two tests varying coils (in second test 2 limiting coils were replaced with 2 TQS coils tested 3 times). MJR strand. Result: first test with very low pre-stress reached ~70% of conductor limit at 4. 5 K and ~86% at 1. 9 K, second test reached ~ 85% of conductor limit at 4. 5 K and ~ 90 % at 1. 9 K. 16

TQS 01 Training • TQS 01 a • 180 to 193 T/m 11 quenches

TQS 01 Training • TQS 01 a • 180 to 193 T/m 11 quenches • Plateau coil 6 • TQS 02 b • 170 to 180 T/m 4 quenches • Plateau coil 14 • TQS 01 c • 160 to 175 T/m 8 quenches (4. 4 K) (max at 182 T/m at high MIITS) • 175 to 192 T/m 20 quenches (1. 9 K) • Plateau coil 15 • All layer 1 pole quenches in the straight section Video conference October 3, 2007 17 17

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Stress, measured and calculated LARP Collaboration Meeting 9, SLAC- Oct 18 -20, 2007 20

Stress, measured and calculated LARP Collaboration Meeting 9, SLAC- Oct 18 -20, 2007 20 20

TQS and TQC – measured field LARP Collaboration Meeting 9, SLAC- Oct 18 -20,

TQS and TQC – measured field LARP Collaboration Meeting 9, SLAC- Oct 18 -20, 2007 21 21

Nb 3 Sn Mirror Dipole Quench Performance Fermilab base program 1 -m (HFDM 03)

Nb 3 Sn Mirror Dipole Quench Performance Fermilab base program 1 -m (HFDM 03) and 2 -m long (LM 01) PIT mirror models reached SSL and Bmax ~10 T. Their quench performance is practically identical 1 -m long mirror model (HFDM 06) with 1 -mm RRP-108/127 strand reached 97% of its SSL and Bmax>11 T. This result has to be reproduced by the 4 -m long RRP coil (LM 02). 22

Conclusion: LARP has developed 1 m, 90 mm quads that reliably reach 200 T/m

Conclusion: LARP has developed 1 m, 90 mm quads that reliably reach 200 T/m (90% Iss at 4. 2 K). However, the factors affecting quench performance (e. g. , at 1. 9 K) are not yet fully understood. 23

LR (long racetrack) 3. 6 m, common coil Relatively quick check of check for

LR (long racetrack) 3. 6 m, common coil Relatively quick check of check for length effects in coil and shell support structure. Coil from BNL, structure from LBNL. 24

LRS 01 (long racetrack coils in shell support structure) 25

LRS 01 (long racetrack coils in shell support structure) 25

LRS 01 – long racetrack, shell 3. 6 m (4. 5 K). Peak field

LRS 01 – long racetrack, shell 3. 6 m (4. 5 K). Peak field on the coil: 11 T (no aperture) I (plateau) ~ 91% Iss 26

LR Test Results Strain gauge measurement and analysis - axial & azimuthal stress •

LR Test Results Strain gauge measurement and analysis - axial & azimuthal stress • Average of the central gauge measurements • 3 cool-downs in total • During dummy coil test – At 77 K • Axial stress of 200 MPa • Azim. stress of 220 MPa P. Ferracin 27

Conclusions for long coils and shell support structure: Magnet quench performance (~ 90% of

Conclusions for long coils and shell support structure: Magnet quench performance (~ 90% of conductor limit) is nearly as good as that of a 0. 3 m version of the same magnet ok. Shell support structure ok at 1 m, subject to stick-slip at 3. 6 m segment into 1 m lengths, join with pins. The “segmented” version of this magnet will be tested late this year. 28

Conclusion: “Building blocks” – materials, model quadrupoles, 3. 6 m racetrack coils and support

Conclusion: “Building blocks” – materials, model quadrupoles, 3. 6 m racetrack coils and support – are in place. We are ready to move into longer length, larger aperture magnets. 29